In 3GPP (3rd Generation Partnership Project), which is a project aiming to standardize a mobile communication system, utilization of a new frequency band is considered in order to respond to a rapid increase in traffic demand (for example, see Non Patent Document 1).
Here, as a new frequency band, a specific frequency band which includes a plurality of component carriers having a predetermined bandwidth and which is allowed to be used by a plurality of network operators or a plurality of communication systems, may be considered.
As a specific frequency band, a bandwidth used for, for example, Wi-Fi (registered trademark), Bluetooth (registered trademark), and the like, that is, an unlicensed band not requiring a license, may be considered. In 3GPP, a technology is considered where an unlicensed band is used for an LTE system (LAA: Licensed Assisted Access).
In LAA, between a licensed cell (L-Cell: Licensed LTE Cell) in which a licensed band requiring a license is used and an unlicensed cell (U-Cell: Unlicensed LTE Cell) in which an unlicensed band is used, a carrier aggregation is applied.